Anode materials for and methods of making and using same

Abstract

An electrochemically active material includes an alloy represented by general formula (I): SiaTibOcNdMe, (I) where a, b, c, d, and e represent atomic % values, a+b+c+d+e=100, M includes carbon or a transition metal element other than titanium, a>20, a+b+e≥c+d, c≥0, d>5, e≥0, and a/b>0.5. The alloy includes a transition metal silicide, titanium nitride, or titanium oxynitride phase, and the phase has a Schemer grain size that is greater than 2 nm and less than 10 nm.

1 . An electrochemically active material comprising an alloy represented by general formula (I):
   Si a Ti b O c N d M e ,  (I)
   where a, b, c, d, and e represent atomic % values, a+b+c+d+e=100, M comprises carbon or a transition metal element other than titanium, a>20, a+b+e≥c+d, c≥0, d>5, e≥0, and a/b>0.5;   wherein the alloy comprises a transition metal silicide, titanium nitride, or titanium oxynitride phase, and the phase has a Scherrer grain size that is greater than 2 nm and less than 10 nm.   
     
     
         2 .- 22 . (canceled) 
     
     
         23 . The electrochemically active material of  claim 1 , wherein M comprises V, Cr, Mn, Fe, Co, Ni or Cu and/or wherein M comprises carbon. 
     
     
         24 . The electrochemically active material according to  claim 1 , wherein a >40. 
     
     
         25 . The electrochemically active material according to  claim 1 , wherein the alloy comprises a transition metal silicide phase. 
     
     
         26 . The electrochemically active material according to  claim 1 , wherein
 the alloy comprises a phase having x-ray diffraction peaks characteristic of a titanium nitride phase or titanium nitride-like phase in which the largest x-ray diffraction peak associated with the titanium nitride phase or titanium nitride-like phase has a full width at half maximum, as measured using Cu-kα 1  radiation greater than 0.9° 2-theta and less than 4° 2-theta,   and/or   
       wherein the alloy comprises an elemental silicon phase having a Scherrer grain size that is less than or equal to 60 nanometers,
 and/or 
 
       wherein each of the phases of the alloy include one or more grains, and wherein the x-ray diffraction pattern of the alloy comprises no detectible Cu-Kα 1  diffraction peaks whose FWHM correspond to a grain size greater than 60 nm, according to the Scherrer equation,
 and/or 
 
       wherein each of the phases of the alloy include one or more grains, and wherein the x-ray diffraction pattern of the alloy comprises no detectible Cu-Kα 1  diffraction peaks associated with elemental silicon whose FWHM correspond to a grain size greater than 2 nm, according to the Scherrer equation. 
     
     
         27 . The electrochemically active material according to  claim 1 , wherein the alloy has a value of r max,30  that is less than 0.25. and/or wherein the alloy has a value of r max,45  that is less than 0.25. 
     
     
         28 . The electrochemically active material according to  claim 1 , wherein the alloy is in the form of particles comprising a flake morphology and/or wherein the alloy is in the form of a powder having a surface area less than 10 m 2 /g. 
     
     
         29 . The electrochemically active material according to  claim 1 , wherein the alloy has a reversible gravimetric capacity greater than 600 mAh/g and a reversible volumetric capacity greater than 1000 Ah/L. 
     
     
         30 . An electrode composition comprising:
 the electrochemically active material according to  claim 1 ; and   a binder,   
       the electrode composition optionally further comprising graphite. 
     
     
         31 . A negative electrode comprising:
 the electrode composition according to  claim 30 ; and   a current collector.   
     
     
         32 . An electrochemical cell comprising:
 the negative electrode of  claim 31 ;   a positive electrode comprising a positive electrode composition comprising lithium; and   an electrolyte comprising lithium.   
     
     
         33 . An electronic device comprising the electrochemical cell according to  claim 32 . 
     
     
         34 . A method of making an electrochemical cell, the method comprising:
 providing a positive electrode comprising a positive electrode composition comprising lithium;   providing a negative electrode according to  claim 31 ;   providing an electrolyte comprising lithium; and   incorporating the positive electrode, negative electrode, and the electrolyte into an electrochemical cell.   
     
     
         35 . A method of making an alloy, the method comprising:
 ball milling a powder comprising silicon and titanium,   wherein the step of ball milling is carried out in an atmosphere comprising nitrogen, a mixture of nitrogen and oxygen, or air.   
     
     
         36 . The method of  claim 35 , wherein the powder comprises an intermetallic compound comprising silicon and titanium, which intermetallic compound optionally comprises TiSi 2 .